# --------------exampel 1---------------
# i = 0
# while i < 5:
#     print("hello world!")
#     i += 1
# --------------exampel 2---------------
# 计算0-100之间所有数的累加
# i = 0
# total = 0
# while i <= 100:
#     total += i
#     i += 1
# print(total)
# 输出 5050
# --------------exampel 3---------------
# 偶数求和
# i = 0
# result = 0
# while i <= 100:
#     if (i % 2) == 0:
#         result += i
#     i += 1
# print(result)
# 输出：2550
# --------------exampel 4---------------
# 打印小星星
# i = 1
# while i <= 9:
#     print("*" * i)
#     i += 1
# --------------exampel 5---------------
# 99乘法表
i = 1

while i <= 9:
    j = 1
    while j <= i:
        # print(j, "x", i, '=', (j * i), end='  ')
        print("%d x %d = %d" % (j, i, j * i), end='\t')
        j += 1
    i += 1
    print()

# 输出：
# 1 x 1 = 1
# 1 x 2 = 2  2 x 2 = 4
# 1 x 3 = 3  2 x 3 = 6  3 x 3 = 9
# 1 x 4 = 4  2 x 4 = 8  3 x 4 = 12  4 x 4 = 16
# 1 x 5 = 5  2 x 5 = 10  3 x 5 = 15  4 x 5 = 20  5 x 5 = 25
# 1 x 6 = 6  2 x 6 = 12  3 x 6 = 18  4 x 6 = 24  5 x 6 = 30  6 x 6 = 36
# 1 x 7 = 7  2 x 7 = 14  3 x 7 = 21  4 x 7 = 28  5 x 7 = 35  6 x 7 = 42  7 x 7 = 49
# 1 x 8 = 8  2 x 8 = 16  3 x 8 = 24  4 x 8 = 32  5 x 8 = 40  6 x 8 = 48  7 x 8 = 56  8 x 8 = 64
# 1 x 9 = 9  2 x 9 = 18  3 x 9 = 27  4 x 9 = 36  5 x 9 = 45  6 x 9 = 54  7 x 9 = 63  8 x 9 = 72  9 x 9 = 81
